Control - Welcome to BHS Life Sciences · •Ecological control protects people and plants –But does not eradicate the pest –It maintains the ecosystem’s integrity •Integrated

Lecture

Presentation

Lectures by:

Heidi Marcum, Baylor University

Pests and Pest

Control

CHAPTER 13

© 2017 Pearson Education, Inc.

Assignments

• Read ‘Silent Spring’- Due Friday

• World Food Prize- Due Monday

• Chapter 13- Due Next Thursday 2/8

– Pg. 317-340

– Questions 1-10 pg. 340


Pests Introduction

• Fold paper into 3 columns

• Label columns- “Organism,” “Pest,” “Not a Pest”

• As a group, list as many as possible in 5-10

minutes.


Organism Pest Not a Pest


Lecture

Presentation

Lectures by:

Heidi Marcum, Baylor University

Pests and Pest

Control

CHAPTER 13


Bedbugs are a public health problem

• Bedbugs have infested many states in the United States

– They were controlled after WWII, but have resurged to epidemic proportions

– Getting rid of them is extremely difficult

• In 2010, Ohio asked the EPA for permission to use the pesticide Propoxur

– The permit was denied over concerns about the effects on children

– But common foggers don’t work on bedbugs

• Solutions that work include non-chemical controls

– Vacuuming, sealing cracks, heat, removing clutter, monitoring, and diatomaceous earth


There are many types of pests

• Pests: organisms that interfere with human activities– Insects, weeds, molds, pathogens, wild animals

– But this is a human-centered definition

• Agricultural pests: feed on crops, plants, or animals– Insects, fungi, viruses, worms, snails, rodents, birds

– Weeds: compete with crops, forests, grasses

– In 2011, mice in Australia cost $300 million in losses

• Veterinary pests affect domestic animals– Fleas, ticks, mites, screwworm flies

• Medical pests attack humans– They may carry diseases (e.g., mosquitoes)


Agricultural pests and weeds


(a) soybean rust, (b) cotton boll weevil, (c) male medfly,

(d) giant hogweed

Veterinary and medical pests


(a) dog ticks, (b) Anopheles mosquito (can transmit

malaria)

Other types of pests

• Forest pests kill trees and wood products

– The emerald ash borer and Asian longhorned

beetle cost $1.7 billion in government spending

• Stored-product pests live in processed foods

– The tiny Khapra beetle, resistant to many

pesticides, is intercepted 200 times a year in the

United States

– Trained agriculture canines can detect such pests

• Biofouling organisms settle in aquatic

environments

– Interfere with shipping, clog pipes and screens

– Pests also live on fabric, paper, etc.


Emerald ash borer


(a) Borers dig into the bark of ash trees and kill them, (b) Traps

along roads help monitor the borer’s movements

Sniffing out pests


A U.S. Customs and Border Protection agriculture specialist

works with an agricultural detector beagle

The cost of controlling pests

• Pesticides and herbicides are costly

– The United States uses 1.1 billion pounds of

herbicides (to kill plants) and other pesticides (to

kill animals) a year

• In 2007, $39 billion was spent on 5.21 billion

pounds of pesticides used worldwide

• Agricultural technology (monocrops, genetically

identical crops) have boosted yields

– But 20–50% of crops are still lost to pests a year

• Pesticide uses have increased drastically

– We have an unsustainable dependency on them


Pesticide use in the United States, 1964–2007


A change in the way totals were calculated makes it hard to

compare values before and after 1998

Pests and climate change

• It is hard to predict the effects of climate change

on pests

– Insects (medical and agricultural) are increasing

their ranges

– Pathogens will respond to changes in precipitation,

temperature, weather events

– Ticks are increasing in North America

– Crop pests (nematodes, weevils) will increase in

the tropics

– Drought may lower mosquito populations


Different philosophies of pest control

• Chemical treatment of pests: eradicates or

decreases pest numbers

– Gives only short-term protection

– Has highly damaging side effects to other

organisms

• Ecological pest control: long-lasting protection

– Based on knowledge of the pest’s life cycle and

ecological relationships

– May be other organisms or chemicals

– May be highly specific to one organism

– May manipulate some aspect of the ecosystem


What is IPM?

• Ecological control protects people and plants

– But does not eradicate the pest

– It maintains the ecosystem’s integrity

• Integrated pest management (IPM): combines

chemical and ecological control to control pests

– It uses all suitable methods to bring about long-term

management of pests

– Has minimal environmental impact

– Used in developing countries that can’t afford

pesticides or where they pose a health risk


The promises of chemical pesticides

• Pesticides are categorized by the organisms

they kill

– Insecticides (insects), rodenticides (rats, mice), fungicides (fungi), herbicides (plants)

– All can pose hazards to others, including humans

• First-generation pesticides: first substances to

control pests

– Toxic heavy metals: lead, arsenic, mercury, cyanide

– Build up in soils, inhibit plant growth, poison organisms, lose effectiveness, pests gain resistance

• Second-generation pesticides: developed through

synthetic organic chemistry


The DDT story

• DDT is a second-generation pesticide

• Chemist Paul Müller studied DDT in the 1930s

– Dichlorodiphenyltrichloroethane

– First synthesized 50 years earlier

• As a pesticide, it was extremely successful

– Extremely toxic to insects, not humans or mammals

– Very cheap

– Broad spectrum: effective against many insect

pests

– Persistent: provided long-lasting protection so

repeated treatments were not necessary


DDT in war and in peace

• DDT saved millions of lives

– The military used it to control lice (cause typhus fever)

– It also controlled dengue fever, mosquitoes (malaria)

– Müller was awarded the 1948 Nobel Prize

• After World War II, DDT was used to control spruce budworms, mosquitoes, Dutch elm disease

• Farmers could ignore other pest control methods (crop rotation and destruction of crop residues)

– They grew less resistant crops in more areas

• Now, the EPA regulates over 18,000 pesticide products


DDT in war


This 1945 image shows a U.S. soldier spraying DDT

directly on a fellow soldier

Pesticide problems: acute health effects

• In 2012, 86,690 people in the United States

were affected

– Farm workers and employees of pesticide

companies

• Pesticides cause:

– Nausea, abdominal pain, shock, respiratory failure,

allergic reactions, seizures, pneumonia, coma

• Over 1 million people/yr. suffer serious poisoning

• Most acute cases occur in developing countries

– Untrained users have little information on pesticides

– People get sprayed, incorrectly store pesticides, or

drink water from contaminated containers


Pesticides are used unsafely


This farmer in Thailand is spraying pesticides on soybeans

without using protective gear

Pesticide problems: chronic health effects

• Pesticides are applied to fields and orchards

– They are also used to protect harvested food

• Consumers and farmers are exposed to low levels

of pesticides and pesticide residues

– Which may have chronic effects

• Pesticides may cause:

– Cancer (lymphoma, breast cancer)

– Dermatitis, nerve damage, birth defects, infertility

– Disruption of the immune and endocrine systems

– Parkinson’s disease, low white blood cell counts


Pesticides are endocrine disrupters

• Many pesticides affect reproductive hormones

– Increased breast cancer in humans

– Abnormal sexual development in alligators,

fish, etc.

• Very low levels mimic or disrupt estrogenic

hormones (potent sexual chemicals)

• The Endocrine Disruptor Screening Program

– This EPA program has developed procedures for

testing chemicals for endocrine disruption


Adverse environmental effects

• Many bird species declined in the 1950s and 1960s

– DDE and DDT caused eggs of birds at the top of the food chain (e.g., bald eagle, osprey) to break

• Bioaccumulation: over time, small amounts of chemicals build up to toxic levels in organisms

– Many synthetic organic chemicals are soluble and are stored in lipids (fats)

– Organisms can’t metabolize or excrete the chemicals

• Biomagnification: the multiplying effect of bioaccumulation in organisms up the food chain

– Top-level organisms have high levels of contaminants


DDT decimated ospreys


Ospreys and other fish-eating birds were decimated by DDT

but recovered when DDT was banned

Biomagnification of DDT


Organisms absorb pesticides from lower levels, bioaccumulating

and magnifying the concentration of the pesticide

Bedbugs are a public health problem

• Bedbugs have infested many states in the United States (Watch: HP Cities 19:40)

• Solutions that work include non-chemical controls

– Vacuuming, sealing cracks, heat, removing clutter, monitoring, and diatomaceous earth


There are many types of pests

• Pests: organisms that interfere with human activities– Insects, weeds, molds, pathogens, wild animals

– But this is a human-centered definition


• Agricultural pests: feed on crops, plants, or animals

• Veterinary pests affect domestic animals

• Medical pests attack humans


Agricultural pests and weeds


(a) soybean rust, (b) cotton boll weevil, (c) male medfly,

(d) giant hogweed

Veterinary and medical pests


(a) dog ticks, (b) Anopheles mosquito (can transmit

malaria)

Other types of pests

• Forest pests kill trees and wood products

– The emerald ash borer and Asian longhorned

beetle cost $1.7 billion in government spending


• Stored-product pests live in processed foods

• Biofouling organisms settle in aquatic

environments


Sniffing out pests


A U.S. Customs and Border Protection agriculture specialist

works with an agricultural detector beagle


The cost of controlling pests

• Pesticides and herbicides are costly

– The United States uses 1.1 billion pounds of

herbicides (to kill plants) and other pesticides (to

kill animals) a year


Pests and climate change

• It is hard to predict the effects of climate change

on pests


Different philosophies of pest control

• Chemical treatment of pests: eradicates or

decreases pest numbers

• Ecological pest control: long-lasting protection




• (Watch HP Cities 14:00)

What is IPM?

• Ecological control protects people and plants

– But does not eradicate the pest

– It maintains the ecosystem’s integrity



– It uses all suitable methods to bring about long-term

management of pests

– Has minimal environmental impact

– Used in developing countries that can’t afford

pesticides or where they pose a health risk


The promises of chemical pesticides

• Pesticides are categorized by the organisms

they kill

– Insecticides (insects), rodenticides (rats, mice), fungicides (fungi), herbicides (plants)


• First-generation pesticides: first substances to

control pests

• Second-generation pesticides: developed through

synthetic organic chemistry


The DDT story

• DDT is a second-generation pesticide

• Chemist Paul Müller studied DDT in the 1930s

– Dichlorodiphenyltrichloroethane

– First synthesized 50 years earlier


DDT in war and in peace

• DDT saved millions of lives

– The military used it to control lice (cause typhus fever)

– It also controlled dengue fever, mosquitoes (malaria)

– Müller was awarded the 1948 Nobel Prize


• After World War II, DDT was used to control spruce budworms, mosquitoes, Dutch elm disease

• Farmers could ignore other pest control methods (crop rotation and destruction of crop residues)


DDT in war


This 1945 image shows a U.S. soldier spraying DDT

directly on a fellow soldier

Pesticide problems: acute health effects

• In 2012, 86,690 people in the United States

were affected

• Pesticides cause:

– Nausea, abdominal pain, shock, respiratory failure,

allergic reactions, seizures, pneumonia, coma


Pesticide problems: chronic health effects

• Pesticides may cause:

– Cancer (lymphoma, breast cancer)

– Dermatitis, nerve damage, birth defects, infertility

– Disruption of the immune and endocrine systems

– Parkinson’s disease, low white blood cell counts


DDT sprayed from a TIFA (Todd

Insecticidal Fog Applicator)

around model Kay Heffernon to


• Pesticides are applied to fields and orchards

– They are also used to protect harvested food

• Consumers and farmers are exposed to low levels of

pesticides and pesticide residues

– Which may have chronic effects

Pesticides are endocrine disrupters

• Many pesticides affect reproductive hormones

– Increased breast cancer in humans

– Abnormal sexual development in alligators,

fish, etc.

• Very low levels mimic or disrupt estrogenic

hormones (potent sexual chemicals)

• The Endocrine Disruptor Screening Program


Adverse environmental effects

• Many bird species declined in the 1950s and 1960s

– DDE and DDT caused eggs of birds at the top of the food chain (e.g., bald eagle, osprey) to break



• Bioaccumulation: over time, small amounts of chemicals build up to toxic levels in organisms

– Many synthetic organic chemicals are soluble and are stored in lipids (fats)

– Organisms can’t metabolize or excrete the chemicals


• Biomagnification: the multiplying effect of bioaccumulation in organisms up the food chain

– Top-level organisms have high levels of contaminants

DDT decimated ospreys


Ospreys and other fish-eating birds were decimated by DDT

but recovered when DDT was banned

Biomagnification of DDT


Organisms absorb pesticides from lower levels, bioaccumulating

and magnifying the concentration of the pesticide

Silent Spring

• Rachel Carson’s Silent Spring (1962) documented

the effects of uncontrolled use of pesticides in the

United States

What did Carson believe?

What was the purpose of writing Silent Spring?


Pesticide problems: resistance

• Chemical pesticides lose their effectiveness

– More and more quantities must be used

– Newer, more potent pesticides must be developed

• It takes more pesticide to get the same results

– In 1946, 2.2 lb. of pesticide resulted in 60,000

bushels of corn; in 1971, it took 141 lb.

– Losses to pests actually increased

• Many pest species have developed resistance

– Stored product, medical, and veterinary pests


Pesticides are involved in synergistic effects

• Synergistic effects: multiple factors work together

to create an unexpected outcome

• What is causing the decline of bees?

– Colony collapse disorder is not caused by one thing

– It could be a mixture of pests, pathogens, parasites,

viruses, poor nutrition, and stress

– Pesticides can interact with these factors

• Bees exposed to pesticides:

– Had low growth rates, ate less, and had trouble

finding their way back to the hive

– They produced fewer queens and danced less


Pollinators in decline


Colony collapse disorder (CCD) killed these bees in Florida.

CCD has caused a massive world die off of bees.

Evolution at work

• Pesticides destroy sensitive individuals

– The resistant ones survive

• Resistance develops rapidly in r-selected species

– They have high reproductive capacity

• Repeated pesticide applications select for genetic

lines that are highly, or totally, resistant to

pesticides

– The Colorado potato beetle developed resistance to

52 compounds (including cyanide) in 50 years

• Many major pest species are resistant to all of the

principal pesticides


Invertebrate food chains


(a) Food chains exist among insects; (b) This ant lion is using

its powerful jaws to capture an ant; (c) This huntsman spider

is eating a grasshopper

Pesticide problems: resurgence

• Resurgence: occurs after a pest has almost been

eliminated

– The population recovers and even explodes

• Secondary pest outbreak: insects that were

originally of no concern create new problems

– They quickly become resistant to pesticides


• Pesticide treadmill: use of pesticides increases

resistance and secondary-pest outbreaks

– New and larger amounts of pesticides are used

– Resistance and secondary-pest outbreaks occur


Trapping technique


Pheromones lure adult Japanese beetles into traps

Alternatives to using pesticides

• A species becomes a pest only when it causes

significant damage

• Economic threshold: the point where:

– Economic losses of pest damage outweigh the cost

of applying a pesticide


What if pest damage is not significant?

• Insurance spraying: use of pesticides to prevent

losses to pests

• Cosmetic spraying: using pesticides to control

pests that harm only the item’s appearance

– Does not increase yields or nutritional value

– Results in increased use and residues on the

produce


The four approaches of IPM

• Set action thresholds: Monitor and identify

pests: Prevent pests: Control pests:


Why do farmers still use pesticides?

• Farmers need to understand the economic

benefits of natural control through IPM

• At first, pesticides increase yield and profits

• Pest-loss insurance: pays the farmer if crops are

lost due to pests


Integrated pest management


IPM has helped Indonesian rice farmers control

the brown plant hopper

Organically grown food

• Organic farms are small and use traditional

farming methods to grow diverse crops

– They are tied to local economies

• Organic crops have lower yields and cost more

• Organic foods in the United States bring in

$33 billion/year


Catching pests early


On December 23, 2013, one coconut rhinoceros beetle, an

invasive pest on palms, was caught in a trap in Honolulu,

Hawaii. After discovering others, APHIS is coordinating a

response to eradicate it before it can spread.

Regulation of pesticides

• The Federal Insecticide, Fungicide, and

Rodenticide Act (FIFRA) (1947)

– Administered by the EPA

– The EPA has total jurisdiction over the

manufacture, use, sale, and testing of pesticides

– Manufacturers must register and test pesticides

– The EPA can ban or restrict a product that causes

unreasonable adverse effects on the environment


The EPA’s Pesticide Program

• It puts high priority on registering “reduced risk”

pesticides that replace more toxic ones

• Biopesticides: naturally occurring substances that

control pests

– Microbial pesticides (Bt), plant-incorporated

protectants in GM crops, and pheromones

– Can be registered faster than other pesticides

• The EPA has come under fire for giving provisional

registration to hundreds of pesticides

– Without requiring them to be fully tracked or tested


Federal Food, Drug, and Cosmetic Act (1938)

(FFDCA)

• Three agencies are involved in protecting

consumers from pesticides on food:

– EPA: sets allowable tolerances for residues

– FDA: monitors and enforces tolerances on

most foods

– USDA: monitors and enforces tolerances on meat,

poultry, and eggs


• The Delaney clause of the FFDCA says that:

– No detectable residue of a pesticide may be on

food if it presents any risk of cancer

– More sensitive analytical techniques banned more

and more pesticides from use on food


Food Quality Protection Act (FQPA) (1996)

• Eliminated the Delaney clause

• It also amended FIFRA and FFDCA

• The FQPA’s new safety standard sets “a

reasonable certainty of no harm” and requires:

– Special consideration for children exposed to

pesticide residues

– Prohibition of pesticides that carry a risk of cancer

more than one in a million

– All sources of a pesticide must be considered

– All products over 10 years old must be reassessed

– Raw and processed foods have the same standard


Care for kids

• The FQPA requires the EPA to add a 10-fold

safety factor in assessing children’s risks from

pesticides

– Children eat more fruits and vegetables per unit of

body weight

– They are more susceptible to carcinogens and

neurotoxins


Pesticides in developing countries

• The United States exports thousands of tons of

pesticides/yr.

– Some have been banned in the United States

• People in developing nations can be exposed to

toxic pesticides

– Low literacy, weak laws, unfamiliarity with

equipment

• FIFRA requires “informed permission” before

shipping any pesticide banned in the United States

– Permission comes from the purchaser

– The EPA must notify the government of the

importing company’s identity


An international framework for pesticides

• The Rotterdam Convention: an international

treaty that promoted open exchange of information

– About hazardous chemicals (including pesticides)

• Prior informed consent (PIC): exporting

countries inform all potential importing countries:

– About actions they have taken to ban or restrict a

chemical, and label them clearly

• The International Code of Conduct on the

Distribution and Use of Pesticides

– A worldwide guidance document about pesticides


The International Code of Conduct

• Addresses conditions of safe pesticide use

– Both private companies and governments are

responsible for safe pesticide use

• The Stockholm convention (2004) eliminates or

restricts persistent organic pollutants

– Nations will ban 9 of the 12 most dangerous

chemicals

– DDT will only be used for malaria control

– Limits accidental releases of dioxins and furans

– 178 countries and the EU—but not the United

States—were parties to the convention


What about the future?

• Pesticide use illustrates two trends in

environmental science issues:

– The problems of cumulative impacts

– The problems of unintended consequences

• Grassroots action and pressure from public-

interest groups and NGOs are pressuring for:

– Safe and sustainable pest prevention and

management

• We must care for the welfare of all creatures to

solve pest problems in a sustainable manner


Nonpersistent pesticides: the answer?

• Persistent chlorinated hydrocarbons can remain

in the environment for decades

– Many have been banned

• Nonpersistent pesticides are extensively used

– Organic phosphates (malathion, parathion,

chlorpyrifos)

– Carbamates (aldicarb, carbaryl)

– They break down into nontoxic products in a

few weeks

– They do not migrate long distances


Nonpersistent pesticides are dangerous

• They harm non-target organisms

• Nonpersistent pesticides are highly toxic

– The EPA must develop health-based standards to

address the risk of children’s exposure to pesticides

• Carbofuran killed 2 million U.S. birds/year

– The EPA revoked all uses in 2008

• Beneficial insects (bees, butterflies) are highly

sensitive

– Predatory insects and spiders are also harmed

• Resurgences, secondary-pest outbreaks, and

resistance to nonpersistent pesticides occur


Alternative pest control methods

• Ecological control: manipulates natural factors

without damaging the environment or human

health

– Depends on understanding the pest and its

relationship with its host and ecosystem

• Insects have complex life cycles

– Each stage may be vulnerable to abiotic factors,

predators, or parasites

• Four categories of ecological pest control are:

– Cultural control, natural enemies, genetic control,

and natural chemical control


Insects have complex life cycles


Biological control recognizes different life stages and attacks

the insect using this knowledge

Cultural control

• A nonchemical change of environmental factors

– The pest finds the area unsuitable or can’t access

its target

• Cutting lawns too short results in weeds

– Keep grass at least 3 inches long

• Mulch discourages weeds and protects the soil

• Avoid plants that attract pests (e.g., roses)

• Plant plants that repel pests (marigolds)

• Hedgerows, fencerows, and shelterbelts

– Provide refuge for pest predators (birds,

amphibians, praying mantises)


Cultural control of wheat rust


Wheat rust must infest barberry―eliminating this plant

controls the wheat rust

More cultural controls of pests

• Plowing or burning crop residues lowers the chance of diseases

• By rotating crops (changing crops each year), pests of the first crop can’t feed on the second crop

• Mixed plantings lowers crop losses to any one pest

• Trap cropping lures a pest to its favorite plant

• Refuge plants are untreated, and predators survive

• Imported pests are the hardest pests to control

– The U.S. Customs and Border Protection and agriculture departments keep pests out of the United States

– Biological materials are prohibited, quarantined, and so on.


Tomato wilt devastates tomato plants


Growing plants in the same place lets spores in the

soil re-infect plants

Cultural controls decrease disease

• Sewage treatment prevents waterborne diseases

• Proper hygiene prevents lice, fleas, and bedbugs

– Combing hair, bathing, cleaning clothing and

bedding

• Bed nets and mattress covers protect against

mosquitoes, bedbugs, and mites

• Garbage disposal and sealing household cracks

and screens prevent roaches, mice, mosquitoes

• Safe food handling, refrigeration, freezing, and

canning prevent spread of disease and rotting

• Catastrophes increase diseases, sickness, death


Control by natural enemies

• There are four types of natural enemies:

– Predators, parasitoids, pathogens, herbivores

• Predator beetles prevent the non-native wooly

adelgid from killing hemlock trees

• Mealy bugs and caterpillars in Africa are controlled

by parasitic wasps

• “Green muscle” (a fungus) controls desert locusts

• Brazilian weevils control water hyacinth in lakes

• Over 30 weed species are limited by insects


Parasitic wasps


Parasitic wasps use moth caterpillars as their hosts

Protect the natives

• Natural enemies must control the target species

without attacking desirable species

• 1% of 50,000 plant-eating insect species are pests

– The other 99% are controlled by natural enemies

• Conservation: protect natural enemies already

here

– The first step in using natural enemies for control

– Avoid or restrict broad-spectrum chemical

insecticides

– These natural enemies control secondary pests

(which become pests only after using pesticides)


Import aliens as a last resort

• Effective natural enemies are not always available

– We import pests, but not their enemies

• Natural enemies are found in the pest’s native land

– They must be carefully tested before being released

• Introduced species can be a success or failure

– Cane toads, imported to control beetles, overran

Australia’s natives instead

– But a parasitoid wasp has successfully controlled

the cassava mealybug in Africa

• Better science and controls help releases succeed


Cane toads and Hessian flies


Cane toads, introduced to Australia to control beetles in sugar

cane fields, became pests themselves

Plant breeding

• Most insects and plant pathogens attack only one

or a few closely related species

– Incompatible plants are not attacked

• Genetic control strategies: develop genetic traits in

the host species that provide incompatibility

– The hosts are resistant to attack by the pest

• But scientists and disease continue to battle

– Scientists developed wheat resistant to wheat stem

rust, a parasitic fungus

– A new fungus is now spreading to Asia, devastating

wheat


Control with chemical and physical barriers

• Plants can produce substances that are lethal or

repulsive to the pest

– A wheat variety produces a chemical that kills the

larvae of the Hessian fly

– Losses to this pest are less than 1% of the non-

resistant wheat varieties

• Plants can have physical traits that trap pests

– Leaves with hooked hairs trap and hold immature

leafhoppers until they die

– Glandular hairs that secrete a sticky substance trap

other pests


Chemical and physical control of plants


This wheat plant produces a chemical toxic to Hessian flies,

while sticky hairs on this alfalfa plant trap an

immature leafhopper

Biotechnology and Bacillus thuringiensis

• Incorporating the protein coat of a virus into the plant

– The plant becomes resistant to the viral infection

• A gene-silencing chemical that interferes with an insect’s normal molting can be put into pests

• A protein from the bacteria Bt can be put into plants

– Kills larvae from plant-eating insects

– But it is harmless to mammals, birds, other insects

• Resistance to Bt and secondary pests are increasing

– Farmers must plant 20% of their fields in non-Btcrops to provide a refuge for susceptible pests

– The resistance genes are diluted© 2017 Pearson Education, Inc.

Bioengineered potatoes


The plant on the left is not genetically modified, while the one

on the right is resistant to a plant pest

Genetic control with sterile males

• Sterile-insect technique: a natural population is

flooded with sterile males that were raised in a

laboratory

• Screwworm flies lay eggs in wounds of animals

– Causing pain, infection, and death

• Screwworm females mate only once

– Males raised in the lab are sterilized with radiation

– If 100 males are released, there is a 99% chance

the female will mate with a sterile male

• Tsetse flies and others have been eradicated

– Eliminating sleeping sickness in Zanzibar


Natural chemical control is nontoxic and

highly specific

• It can be used as biocides, pesticides from plants,

or in communication or immunity

• Pheromones: influence the behavior of others of

the same species

– Lures pests into traps or eating poisoned bait

– Males become confused and can’t find females

• Hormones: chemicals produced in organisms that

control development and metabolic functions

– They can be used to disrupt a pest’s life cycle

– Mimic: a synthetic hormone that starts, but does

not continue, molting in moths and butterflies


Natural chemical control on crops

• Natural chemicals used on crops can boost

defenses

– Seeds dipped in jasmonic acid (which occurs

naturally) have lower aphid attacks and caterpillar

damage

• Bt can be sprayed into water or crops

– Instead of being incorporated into genetically

modified plants


Trapping technique


Pheromones lure adult Japanese beetles into traps

Alternatives to using pesticides

• There is a growing movement to avoid pesticides

– Availability of alternative pest controls

– Evidence of the failures of chemical treatment

• A species becomes a pest only when it causes

significant damage

• Natural controls keep pests below damaging levels

– They do not try to eradicate the pest

• Economic threshold: the point where:

– Economic losses of pest damage outweigh the cost

of applying a pesticide


The economic threshold


Pest control is not about eradication―the population just

needs to be kept below the economic threshold

What if pest damage is not significant?

• If significant crop damage is not occurring and

natural controls are working?

– Leave the situation alone because chemicals upset

the natural balance and are not cost-effective

• Insurance spraying: use of pesticides to prevent

losses to pests

• Cosmetic spraying: using pesticides to control

pests that harm only the item’s appearance

– Does not increase yields or nutritional value

– Results in increased use and residues on the

produce



• IPM aims to minimize use of synthetic organic

pesticides without jeopardizing crops

– Includes all factors in crop protection

– Crop and pests are seen as parts of a dynamic

system

• The goal is not pest eradication, but keeping crop

damage below the economic threshold

• The EPA’s four-tiered approach to IPM:

– Set action thresholds, monitor and identify pests,

prevent pests, and control pests


The four approaches of IPM

• Set action thresholds: identify the point where

conditions indicate that some control is needed

• Monitor and identify pests: experts determine if

pests exceed the economic threshold

– Extension services, farm cooperatives, consultants

– Field scouts: trained to identify and monitor pests

• Prevent pests: use cultural and biological controls

– Crop rotation, predators, fertilizing, “trap crops”

• Control pests: select pesticides that do the least

damage to natural enemies of the pest


Why do farmers still use pesticides?

• Farmers need to understand the economic

benefits of natural control through IPM

• At first, pesticides increase yield and profits

– Farmers think they are the only option for profit

– Rising pesticide costs and harm eliminated

pesticides’ economic advantage

• Pest-loss insurance: pays the farmer if crops are

lost due to pests

– Growers don’t do unnecessary and costly

“insurance spraying”


IPM can control malarial mosquitoes

• Cultural controls are used on mosquitoes

– Pesticide-impregnated nets, removal of breeding

sites

– Bt, natural enemies (birds, insects)

– A fungus kills larvae, while bacteria prevent

mosquitoes from passing the malarial parasite on

– The sterile male technique is being tested

– A virus kills the older adults that pass on the

disease


The Indonesian IPM program

• Government policies determine if IPM is used

– Governments and agencies subsidize pesticides

– Encourage growers to step on the pesticide

treadmill

• The Indonesian government used IPM to control


– Rice growers switched from heavy pesticide use to

light spraying

– Preserves the enemies of the insect

• FAO workers trained farmers

– Who in turn trained others


Brown plant hoppers


These immature brown plant hoppers are shown on the stem

of a rice plant

The Indonesian IPM program succeeded

• The economic and environmental benefits have

been remarkable

– The government saved millions by not buying

pesticides

– Farmers have not had to buy pesticides and

equipment

– Thousands of tons of pesticides did not enter the

environment

– Fish are thriving in the rice paddies

– Farmers, consumers, and wildlife have increased

health benefits from reduced pesticide use




IPM has helped Indonesian rice farmers control


Organically grown food

• Many farmers are turning away from pesticides,

chemical fertilizers, antibiotics, and hormones

– For grains, vegetables, and livestock

• Organic farms are small and use traditional

farming methods to grow diverse crops

– They are tied to local economies

• Organic crops have lower yields and cost more

– But also incur lower expenses

– Crops lack, or have much smaller, pesticide

residues

• Organic foods in the United States bring in

$33 billion/year


Organic foods


This symbol on food signals that the food or crop was

produced on a certified organic farm

USDA certifies organic food

• Organic Foods Protection Act (1990)

– Established the National Organic Standards Board

(NOSB) under the USDA

• Standards for certifying organic foods prohibits:

– Genetically engineered or irradiated food

– Fertilizing with sludge or chemicals

– Conventional pesticides, antibiotics, growth

hormones, chemical fertilizers

• Farmers must be inspected to use the organic seal

• If food is at least 95% organic, they can use the

seal—but cannot claim to be 100% organic


Regulation of pests

• The United States has many guidelines for federal

and state agencies to protect food safety

– To monitor, eradicate, and prevent pests

• International treaties exist to lower the impact of

pests and prevent misuse of dangerous pesticides

• The USDA’s Animal and Plant Health Inspection

Service (APHIS) monitors and controls pests

– It consolidated multiple agencies involved with

animals and plants

– It regulates animals used in research and exhibition

and by dealers


The APHIS

• APHIS monitors potential pests to prevent

outbreaks

• For example, soybean rust devastated crops

in Brazil

– Hurricane Irene blew this fungus into the

United States

– APHIS set up a Web-based tracking system

– Governmental agencies, universities, and farmers

used rigorously surveyed “sentinel plots”

– These actions successfully prevented an epidemic

in the United States


Plant Protection Act

• Plants in the United States have been regulated

since 1912

– The 2000 Plant Protection Act consolidated all acts

• Duties of the Plant Protection Act include:

– Noxious weeds cannot be moved across state lines,

imported, or exported

• APHIS regulates imports and exports to prevent

movement of pests

– In 2012 ash tree products and firewood were

regulated to stop the emerald ash borer


APHIS’ role has expanded

• It monitors pests that might attack wildlife and monitors bioengineered species

• It regulates the welfare of domestic animals

• It protects plant and animal agriculture from disease

– It tracks efforts to eradicate animal and plant diseases

– After detecting a bacterial disease that had come from Kenya, it temporarily stopped imports of geraniums

• The Agricultural Bioterrorism Protection Act (2002)

– Regulates labs and vaccine companies

• APHIS assessments are open to public review


Catching pests early


On December 23, 2013, one coconut rhinoceros beetle, an

invasive pest on palms, was caught in a trap in Honolulu,

Hawaii. After discovering others, APHIS is coordinating a

response to eradicate it before it can spread.

The United States collaborates with other

nations

• U.S. agencies collaborate with other nations to

prevent the spread of pest organisms

• The International Plant Protection Convention

– The IPPC set up an international system to

quarantine products to prevent pest spread

• The 1995 United Nations Convention on the Law

of the Sea (UNCLOS)

– Prevents the introduction of marine species to

new areas

• Other international agreements also help prevent

the spread of plant diseases and other pests


Regulation of pesticides

• Pesticide regulation focuses on three main areas:

– Safety and testing of pesticides, and protection of

pesticide workers and consumers

• The Federal Insecticide, Fungicide, and

Rodenticide Act (FIFRA) (1947)

– Administered by the EPA

– The EPA has total jurisdiction over the

manufacture, use, sale, and testing of pesticides

– Manufacturers must register and test pesticides

– The EPA can ban or restrict a product that causes

unreasonable adverse effects on the environment


The EPA’s Pesticide Program

• It puts high priority on registering “reduced risk”

pesticides that replace more toxic ones

• Biopesticides: naturally occurring substances that

control pests

– Microbial pesticides (Bt), plant-incorporated

protectants in GM crops, and pheromones

– Can be registered faster than other pesticides

• The EPA has come under fire for giving provisional

registration to hundreds of pesticides

– Without requiring them to be fully tracked or tested


Federal Food, Drug, and Cosmetic Act (1938)

(FFDCA)

• Three agencies are involved in protecting

consumers from pesticides on food:

– EPA: sets allowable tolerances for residues

– FDA: monitors and enforces tolerances on

most foods

– USDA: monitors and enforces tolerances on meat,

poultry, and eggs

• The Delaney clause of the FFDCA says that:

– No detectable residue of a pesticide may be on

food if it presents any risk of cancer

– More sensitive analytical techniques banned more

and more pesticides from use on food© 2017 Pearson Education, Inc.

Food Quality Protection Act (FQPA) (1996)

• Eliminated the Delaney clause

• It also amended FIFRA and FFDCA

• The FQPA’s new safety standard sets “a

reasonable certainty of no harm” and requires:

– Special consideration for children exposed to

pesticide residues

– Prohibition of pesticides that carry a risk of cancer

more than one in a million

– All sources of a pesticide must be considered

– All products over 10 years old must be reassessed

– Raw and processed foods have the same standard


Care for kids

• The FQPA requires the EPA to add a 10-fold

safety factor in assessing children’s risks from

pesticides

– Children eat more fruits and vegetables per unit of

body weight

– They are more susceptible to carcinogens and

neurotoxins


Pesticides in developing countries

• The United States exports thousands of tons of

pesticides/yr.

– Some have been banned in the United States

• People in developing nations can be exposed to

toxic pesticides

– Low literacy, weak laws, unfamiliarity with

equipment

• FIFRA requires “informed permission” before

shipping any pesticide banned in the United States

– Permission comes from the purchaser

– The EPA must notify the government of the

importing company’s identity


An international framework for pesticides

• The Rotterdam Convention: an international

treaty that promoted open exchange of information

– About hazardous chemicals (including pesticides)

• Prior informed consent (PIC): exporting

countries inform all potential importing countries:

– About actions they have taken to ban or restrict a

chemical, and label them clearly

• The International Code of Conduct on the

Distribution and Use of Pesticides

– A worldwide guidance document about pesticides


The International Code of Conduct

• Addresses conditions of safe pesticide use

– Both private companies and governments are

responsible for safe pesticide use

• The Stockholm convention (2004) eliminates or

restricts persistent organic pollutants

– Nations will ban 9 of the 12 most dangerous

chemicals

– DDT will only be used for malaria control

– Limits accidental releases of dioxins and furans

– 178 countries and the EU—but not the United

States—were parties to the convention


What about the future?

• Pesticide use illustrates two trends in

environmental science issues:

– The problems of cumulative impacts

– The problems of unintended consequences

• Grassroots action and pressure from public-

interest groups and NGOs are pressuring for:

– Safe and sustainable pest prevention and

management

• We must care for the welfare of all creatures to

solve pest problems in a sustainable manner


Documents

Control - Welcome to BHS Life Sciences · •Ecological control protects people and plants –But does not eradicate the pest –It maintains the ecosystem’s integrity •Integrated